president obama will travel to boston for a memorial service on thursday. the u.s. senate has shut its mail facility for the next couple days after authorities intercepted a letter sent to mississippi republican roger wicker. it was laced with the poison ricin. the letter was post marked from tennessee but had no return address. >>> here in london we are watching the funeral procession for the former british prime minister margaret thatcher. that funeral is due to begin in just about an hour's time at st. paul's cathedral. just outside our studios in london. ross westgate is not with me because he's outside of the cathedral. it looks as though they nearly have arrived. they still have an hour left to go. >> the hearse which you saw creeping behind the church there is just about a half mile away from st. paul's cathedral. it also pretty much marks the spot where the west end becomes the city of london or the city of london that's under the control of the corporation of the city of london. what will happen there is that the hearse will stop and lady thatcher's body an